1 files changed, 427 insertions, 0 deletions

diff --git a/Alsa-Plugin/Alsa-Policy-Hook/AlsaHookCb.c b/Alsa-Plugin/Alsa-Policy-Hook/AlsaHookCb.c
new file mode 100644
index 0000000..2675805
--- /dev/null
+++ b/Alsa-Plugin/Alsa-Policy-Hook/AlsaHookCb.c
@@ -0,0 +1,427 @@
+/*
+ * Copyright (C) 2016 "IoT.bzh"
+ * Author Fulup Ar Foll <fulup@iot.bzh>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * 
+ * AfbCallBack (snd_ctl_hal_t *handle, int numid, void **response);
+ *  AlsaHookInit is mandatory and called with numid=0
+ * 
+ * Syntax in .asoundrc file
+ *   CrlLabel    { cb MyFunctionName name "My_Second_Control" }
+ * 
+ * Testing:
+ *   aplay -DAlsaHook /usr/share/sounds/alsa/test.wav 
+ * 
+ * References:
+ *  https://www.spinics.net/lists/alsa-devel/msg54235.html
+ *  https://github.com/shivdasgujare/utilities/blob/master/nexuss/alsa-scenario-hook/src/alsa-wrapper.c
+ */
+
+#define _GNU_SOURCE  
+#include <stdio.h>
+#include <alsa/asoundlib.h>
+#include <alsa/conf.h>
+#include <alsa/pcm.h>
+
+#include <systemd/sd-event.h>
+#include <json-c/json.h>
+
+#include "afb/afb-wsj1.h"
+#include "afb/afb-ws-client.h"
+#include <pthread.h>
+#include <semaphore.h>
+
+
+#define PLUGIN_ENTRY_POINT AlsaInstallHook
+    // Fulup Note: What ever you may find on Internet you should use
+    // SND_CONFIG_DLSYM_VERSION_HOOK and not SND_CONFIG_DLSYM_VERSION_HOOK
+    SND_DLSYM_BUILD_VERSION(PLUGIN_ENTRY_POINT, SND_PCM_DLSYM_VERSION)
+
+// this should be more than enough
+#define MAX_API_CALL 10
+
+// Currently not implemented
+#define UNUSED(x) UNUSED_ ## x __attribute__((__unused__))
+#define UNUSED_FUNCTION(x) __attribute__((__unused__)) UNUSED_ ## x
+void OnRequestCB(void* UNUSED(handle) , const char* UNUSED(api), const char* UNUSED(verb), struct afb_wsj1_msg*UNUSED(msg)) {}
+
+    typedef struct {
+    snd_pcm_t *pcm;
+    const char *uri;
+    struct afb_wsj1 *wsj1;
+    sd_event *sdLoop;
+    int verbose;
+    sem_t semaphore;
+    int count;
+    int error;
+} afbClientT;
+
+typedef struct {
+    const char *api;
+    const char *verb;
+    long timeout;
+    char *query;
+    
+    sd_event_source *evtSource;
+    char *callIdTag;
+    afbClientT *afbClient;
+} afbRequestT;
+
+static void *LoopInThread(void *handle) {
+    afbClientT *afbClient = (afbClientT*) handle;
+    int count=0;
+    int watchdog= 60 *1000000;
+
+    /* loop until end */
+    for (;;) {
+        
+        if (afbClient->verbose) printf("ON-MAINLOOP Active count=%d\n", count++);
+        sd_event_run(afbClient->sdLoop, watchdog);
+    }
+
+    return NULL;
+}
+
+// lost connect with the AudioDaemon
+static void OnHangupCB(void *handle, struct afb_wsj1 *wsj1) {
+
+    afbClientT *afbClient = (afbClientT*) handle;
+    snd_pcm_close (afbClient->pcm);
+
+    SNDERR("(Hoops) Lost Connection to %s", afbClient->uri);
+    exit(0);
+}
+
+void OnEventCB(void *handle, const char *event, struct afb_wsj1_msg *msg) {
+    afbClientT *afbClient = (afbClientT*) handle;
+    int err;
+    
+    printf("ON-EVENT %s(%s)\n", event, afb_wsj1_msg_object_s(msg));
+    
+    // pause PCM until request call succeed    
+    err = snd_pcm_pause (afbClient->pcm, 1);
+    if (err < 0) {
+        fprintf (stderr, "PCM Fail to pause\n");
+        goto OnErrorExit;
+    }
+    
+    // wait on a semaphore until request return or timeout
+    err = snd_pcm_pause (afbClient->pcm, 0);
+    if (err < 0) {
+        fprintf (stderr, "PCM Fail to resume\n");
+        goto OnErrorExit;
+    }
+    
+OnErrorExit:
+    return;
+    
+}
+
+// callback interface for wsj1
+static struct afb_wsj1_itf itf = {
+    .on_hangup = OnHangupCB,
+    .on_call = OnRequestCB,
+    .on_event = OnEventCB
+};
+
+void OnAbortPcm (afbClientT *afbClient) {
+    printf("ON-ABORT-PCM PCM=%s URI=%s\n", snd_pcm_name(afbClient->pcm), afbClient->uri);
+    snd_pcm_close (afbClient->pcm);
+}
+
+void OnResponseCB(void *handle, struct afb_wsj1_msg *msg) {
+    afbRequestT *afbRequest= (afbRequestT*)handle;
+
+    if (afbRequest->afbClient->verbose) printf("ON-RESPONSE call=%s response=%s\n", afbRequest->callIdTag, afb_wsj1_msg_object_s(msg));
+    
+    // Cancel timeout for this request
+    sd_event_source_unref(afbRequest->evtSource);
+    
+    if (! afb_wsj1_msg_is_reply_ok(msg)) {
+        fprintf(stderr, "ON-RESPONSE ERROR call=%s response=%s\n", afbRequest->callIdTag, afb_wsj1_msg_object_s(msg));
+        OnAbortPcm (afbRequest->afbClient);
+    } 
+    
+    // When not more waiting call release semaphore
+    afbRequest->afbClient->count--;
+    if (afbRequest->afbClient->count == 0) {
+        if (afbRequest->afbClient->verbose) printf("ON-RESPONSE No More Waiting Request\n");
+        afbRequest->afbClient->error=0;
+        sem_post (&afbRequest->afbClient->semaphore);
+    }
+}
+
+int OnTimeoutCB (sd_event_source* source, uint64_t timer, void* handle) {
+    afbClientT *afbClient= (afbClientT*)handle;
+
+    fprintf(stderr, "ON-TIMEOUT Call Request Fail URI=%s\n", afbClient->uri);
+    
+    // Close PCM and release waiting client
+    afbClient->error=1;
+    sem_post (&afbClient->semaphore);          
+    
+    return 0;
+}
+
+// Call AGL binder asynchronously by with a timeout
+static int CallWithTimeout(afbClientT *afbClient, afbRequestT *afbRequest, int count) {
+    uint64_t usec;
+    int err;
+
+    // create a unique tag for request
+    (void) asprintf(&afbRequest->callIdTag, "%d:%s/%s", count, afbRequest->api, afbRequest->verb);
+
+    err = afb_wsj1_call_s(afbClient->wsj1, afbRequest->api, afbRequest->verb, afbRequest->query, OnResponseCB, afbRequest);
+    if (err) goto OnErrorExit;
+    
+    // create a timer with ~250us accuracy
+    sd_event_now(afbClient->sdLoop, CLOCK_MONOTONIC, &usec);
+    sd_event_add_time(afbClient->sdLoop, &afbRequest->evtSource, CLOCK_MONOTONIC, usec+afbRequest->timeout*1000, 250, OnTimeoutCB, afbClient);
+
+    // save client handle in request
+    afbRequest->afbClient = afbClient;
+    afbClient->count ++;
+    
+    return 0;
+    
+OnErrorExit:
+    return -1;
+}
+
+static int LaunchCallRequest(afbClientT *afbClient, afbRequestT **afbRequest) {
+
+    pthread_t tid;
+    int err, idx;
+
+    // Create a main loop
+    err = sd_event_default(&afbClient->sdLoop);
+    if (err < 0) {
+        fprintf(stderr, "LaunchCallRequest: Connection to default event loop failed: %s\n", strerror(-err));
+        goto OnErrorExit;
+    }
+    
+    // init waiting counting semaphore
+    if (sem_init(&afbClient->semaphore, 1, 0) == -1) {
+       fprintf(stderr, "LaunchCallRequest: Fail Semaphore Init: %s\n", afbClient->uri); 
+    }
+    
+    // connect the websocket wsj1 to the uri given by the first argument 
+    afbClient->wsj1 = afb_ws_client_connect_wsj1(afbClient->sdLoop, afbClient->uri, &itf, afbClient);
+    if (afbClient->wsj1 == NULL) {
+        fprintf(stderr, "LaunchCallRequest: Connection to %s failed\n", afbClient->uri);
+        goto OnErrorExit;
+    }
+
+    // send call request to audio-agent asynchronously (respond with thread mainloop context)
+    for (idx = 0; afbRequest[idx] != NULL; idx++) {
+        err = CallWithTimeout(afbClient, afbRequest[idx], idx);
+        if (err) {
+            fprintf(stderr, "LaunchCallRequest: Fail call %s//%s/%s&%s", afbClient->uri, afbRequest[idx]->api, afbRequest[idx]->verb, afbRequest[idx]->query);
+            goto OnErrorExit;
+        }        
+    }
+    
+    // launch counter to keep track of waiting request call
+    afbClient->count=idx;
+
+    // start a thread with a mainloop to monitor Audio-Agent
+    err = pthread_create(&tid, NULL, &LoopInThread, afbClient);
+    if (err) goto OnErrorExit;
+    
+    return 0;
+
+OnErrorExit:
+    return -1;
+}
+
+static int AlsaCloseHook(snd_pcm_hook_t *hook) {
+
+    afbClientT *afbClient = (afbClientT*) snd_pcm_hook_get_private (hook);
+    
+    if (afbClient->verbose) fprintf(stdout, "\nAlsaCloseHook pcm=%s uri=%s\n", snd_pcm_name(afbClient->pcm), afbClient->uri);
+    return 0;
+}
+
+// Function call when Plugin PCM is OPEN
+int PLUGIN_ENTRY_POINT (snd_pcm_t *pcm, snd_config_t *conf) {
+    afbRequestT **afbRequest;
+    snd_pcm_hook_t *h_close = NULL;
+    snd_config_iterator_t it, next;
+    afbClientT *afbClient = malloc(sizeof (afbClientT));
+    afbRequest = malloc(MAX_API_CALL * sizeof (afbRequestT));
+    int err;
+
+    // start populating client handle
+    afbClient->pcm = pcm;
+    afbClient->verbose = 0;
+
+    
+    // Get PCM arguments from asoundrc
+    snd_config_for_each(it, next, conf) {
+        snd_config_t *node = snd_config_iterator_entry(it);
+        const char *id;
+
+        // ignore comment en empty lines
+        if (snd_config_get_id(node, &id) < 0) continue;
+        if (strcmp(id, "comment") == 0 || strcmp(id, "hint") == 0) continue;
+
+        if (strcmp(id, "uri") == 0) {
+            if (snd_config_get_string(node, &afbClient->uri) < 0) {
+                SNDERR("Invalid String for %s", id);
+                goto OnErrorExit;
+            }
+            continue;
+        }
+
+        if (strcmp(id, "verbose") == 0) {
+            afbClient->verbose= snd_config_get_bool(node);
+            if (afbClient->verbose < 0) {
+                SNDERR("Invalid Boolean for %s", id);
+                goto OnErrorExit;
+            }
+            continue;
+        }
+
+        if (strcmp(id, "request") == 0) {
+            const char *callConf, *callLabel;
+            snd_config_type_t ctype;
+            snd_config_iterator_t currentCall, follow;
+            snd_config_t *itemConf;
+            int callCount=0;
+
+            ctype = snd_config_get_type(node);
+            if (ctype != SND_CONFIG_TYPE_COMPOUND) {
+                snd_config_get_string(node, &callConf);
+                SNDERR("Invalid compound type for %s", callConf);
+                goto OnErrorExit;
+            }
+
+
+            // loop on each call 
+            snd_config_for_each(currentCall, follow, node) {
+                snd_config_t *ctlconfig = snd_config_iterator_entry(currentCall);
+                
+                // ignore empty line
+                if (snd_config_get_id(ctlconfig, &callLabel) < 0) continue;
+
+                // each clt should be a valid config compound
+                ctype = snd_config_get_type(ctlconfig);
+                if (ctype != SND_CONFIG_TYPE_COMPOUND) {
+                    snd_config_get_string(node, &callConf);
+                    SNDERR("Invalid call element for %s", callLabel);
+                    goto OnErrorExit;
+                }
+
+                // allocate an empty call request
+                afbRequest[callCount] = malloc(sizeof (afbRequestT));
+                afbRequest[callCount]->api=NULL;
+                afbRequest[callCount]->verb=NULL;
+                afbRequest[callCount]->query=NULL;
+
+
+                err = snd_config_search(ctlconfig, "api", &itemConf);
+                if (!err) {
+                    if (snd_config_get_string(itemConf, &afbRequest[callCount]->api) < 0) {
+                        SNDERR("Invalid api string for %s", callLabel);
+                        goto OnErrorExit;
+                    }
+                }
+                
+                err = snd_config_search(ctlconfig, "verb", &itemConf);
+                if (!err) {
+                    if (snd_config_get_string(itemConf, &afbRequest[callCount]->verb) < 0) {
+                        SNDERR("Invalid verb string %s", id);
+                        goto OnErrorExit;
+                    }
+                }
+                
+                err = snd_config_search(ctlconfig, "timeout", &itemConf);
+                if (!err) {
+                    if (snd_config_get_integer(itemConf, &afbRequest[callCount]->timeout) < 0) {
+                        SNDERR("Invalid timeout Integer %s", id);
+                        goto OnErrorExit;
+                    }
+                }
+                
+                err = snd_config_search(ctlconfig, "query", &itemConf);
+                if (!err) {
+                    const char *query;
+                    if (snd_config_get_string(itemConf, &query) < 0) {
+                        SNDERR("Invalid query string %s", id);
+                        goto OnErrorExit;
+                    }
+                    // cleanup string for json_tokener
+                    afbRequest[callCount]->query = strdup(query);
+                    for (int idx = 0; query[idx] != '\0'; idx++) {
+                        if (query[idx] == '\'') afbRequest[callCount]->query[idx] = '"';
+                        else afbRequest[callCount]->query[idx] = query[idx];
+                    }
+                    json_object *queryJ = json_tokener_parse(query);
+                    if (!queryJ) {
+                        SNDERR("Invalid Json %s query=%s format \"{'tok1':'val1', 'tok2':'val2'}\" ", id, query);
+                        goto OnErrorExit;
+                    }
+                }
+                
+                // Simple check on call request validity
+                if (!afbRequest[callCount]->query)   afbRequest[callCount]->query= "";
+                if (!afbRequest[callCount]->timeout) afbRequest[callCount]->timeout=100;
+                if (!afbRequest[callCount]->verb || !afbRequest[callCount]->api) {
+                    SNDERR("Missing api/verb %s in asoundrc", callLabel);
+                    goto OnErrorExit;
+                }
+
+                // move to next call if any
+                callCount ++;
+                if (callCount == MAX_API_CALL) {
+                    SNDERR("Too Many call MAX_API_CALL=%d", MAX_API_CALL);
+                    goto OnErrorExit;                    
+                }
+                afbRequest[callCount]=NULL; // afbRequest array is NULL terminated
+
+            } 
+            continue;
+        }
+    }
+    
+    if (afbClient->verbose) fprintf(stdout, "\nAlsaHook Install Start PCM=%s URI=%s\n", snd_pcm_name(afbClient->pcm), afbClient->uri);
+
+    err = snd_pcm_hook_add(&h_close, afbClient->pcm, SND_PCM_HOOK_TYPE_CLOSE, AlsaCloseHook, afbClient);
+    if (err < 0) goto OnErrorExit;
+
+    // launch call request and create a waiting mainloop thread
+    err = LaunchCallRequest(afbClient, afbRequest);
+    if (err < 0) {
+        fprintf (stderr, "PCM Fail to Enter Mainloop\n");
+        goto OnErrorExit;
+    }
+    
+    // wait for all call request to return
+    sem_wait(&afbClient->semaphore);
+    if (afbClient->error) {
+        fprintf (stderr, "PCM Authorisation from Audio Agent Refused\n");
+        goto OnErrorExit;        
+    }
+
+    if (afbClient->verbose) fprintf(stdout, "\nAlsaHook Install Success PCM=%s URI=%s\n", snd_pcm_name(afbClient->pcm), afbClient->uri);
+    return 0;
+
+OnErrorExit:
+    fprintf(stderr, "\nAlsaPcmHook Plugin Install Fail PCM=%s\n", snd_pcm_name(afbClient->pcm));
+    if (h_close)
+        snd_pcm_hook_remove(h_close);
+
+    return -EINVAL;
+}
+